1. Field of the Invention
This invention relates to a binary vapor cycle method of electrical power generation and production of mechanical power which is applicable to the utilization of low specific energy sources, such as two water sources which exist in close proximity to each other, but at different temperatures. This method is essentially a dual heat pump system in which the heat pump fluid of the first heat pump system is the water, or other fluid, of the warm fluid source, and the heat pump fluid of the second heat pump system can be a refrigerant that has properties that include high changes in saturation pressure with small changes in temperature. Thus, water from the warm water source, which in itself is a heat pump fluid, can be used as a means of transmitting heat energy to the second heat pump, without incurring the disadvantages of water as a refrigerant to produce power, because of its high specific volume and low saturation pressures, negative, at low temperatures. Additionally, since the warm water source of energy most commonly available is contained in the form of reservoirs, such as the ocean waters, barometric legs can be used to bring the warm water source into thermal contact with the process, eliminating the use of expensive heat exchangers, which in the case of ocean water, are subject to fouling and loss of efficiency due to clinging microorganisms.
The process and apparatus hereinafter described is, for clarity, specifically a description of the use of the process and apparatus with a warm water source and a cold water source, such as the ocean waters, it being understood that the principles described here are pertinent to any such applications where sufficient fluid temperature differentials exist.
2. Description of the Prior Art
As the worlds sources of fossilized fuels are rapidly depleting, the alternate sources of power under strict scrutiny include the so-called natural energies, such as solar power, indirect solar power, geo-thermal power, etc. One of the many faceted solutions to the development of new sources of energy appears to lie in the utilization of the energy differentials existing between two fluid sources at different temperatures, such as are present in tropical ocean waters, wherein the warm surface waters, which are solar heated, are at temperatures considerably higher than the cold deep oceans waters.
Although the total energy existing in two large fluid sources at different temperatures, such as exist in ocean waters, is enormous, the specific energy, the energy existing per unit of weight or mass is very small indeed, necessitating new and novel techniques and cycles to utilize the small amount of specific energy available to do productive work.
The heat pump has been known as one of the most efficient method for heating and cooling with the application of small amounts of external energy. Application of heat pump principles appear to offer the solutions for obtaining usable energy from the aforementioned low specific energy sources. Previously, heat pump systems have been designed to obtain the maximum amount of heat transfer from one source to another source with the minimum amount of power applied. To utilize heat sources of low specific energy for the production of energy, it is now necessary to devise heat pump systems that will produce the maximum amount of energy with the minimum amount of heat energy applied.
Therefore it is an object of this invention to provide a process and an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the pertinent art.
Accordingly, it is an object of the present invention to provide a novel and improved heat pump system which is operable to produce mechanical power and/or electrical power using a warm fluid source for supplying heat to offset the heat loss which occurs during vaporization of a fluid and a cold source to effect condensing of the fluid vapors.
It is also an object of the present invention to provide a process and an apparatus whereby a first heat pump system derives heat energy of a warm water source and delivers said heat energy to the evaporator of a second heat pump system, the heat exchanger means of the evaporator of the second heat pump system being the condensing means of the first heat pump system.
It is also an object of the present invention to provide a process and an apparatus wherein the first heat pump system becomes the warm source, or energy source, for a second heat pump system wherein mechanical power and electrical power are produced.
It is another object of the present invention to provide a process and an apparatus wherein the second heat pump into which a prime mover has been interposed which is driven by the pressure difference between an evaporator section of the apparatus, which contains a refrigerant and is at the saturation pressure of the refrigerant for the corresponding temperature of the refrigerant, which is heated by the first heat pump, and the lower saturation pressure of the cooler refrigerant in the condenser section of the apparatus, which is cooled by the cold fluid source, and the mass flow of refrigerant vapors between the evaporator and the condenser sections of the apparatus.
It is a further object of the present invention to provide a means of converting all or part of the output of said prime mover means to electrical energy by means of an electrical generator means and an electrical control means.
It is still another object of the present invention to provide a controlled means, within the second heat pump system, of returning the condensed refrigerant, liquid, from the condenser means to the evaporator means to replace the said refrigerant evaporated in the said evaporator means.
A further object of the present invention is to provide a means, within the second heat pump, of controlling the speed of the prime mover means regardless of variations in the load on the generator means, by means of a control valve means and conduit means in parallel with the prime mover means which is capable of by-passing a portion of the flow of refrigerant vapors from the evaporator means to the condenser means, thereby controlling the pressure across the prime mover means.
Yet another object of the present invention is to provide a heat exchanger means and a pump means to bring the refrigerant in the evaporator means, of the second heat pump system, into thermal contact with the water vapors in the condenser means of the first heat pump system. The heat of condensation of the vapors in the condenser means of the first heat pump in thermal contact with the said heat exchanger provides the means by which the heat of vaporization lost in the evaporator of the second heat pump is constantly being replaced.
Still another object of the present invention is to provide a heat exchanger means within the condenser means of the second heat pump system, wherein the refrigerant vapors of the second heat pump system within the condenser means are brought into thermal contact with the cooling, or condensing, water, removing the heat of condensation, which is equal to the heat of vaporization.
Another object of the present invention is to provide a means of removing condensate water from the condenser means of the first heat pump system by means of a barometric conduit, or alternatively, removing said condensate water by conventional pump and conduit means, or alternatively, returning the said condensate water to the water source by means of a barometric conduit.
It is still another object of the present invention to provide, within the first heat pump system, a process and an apparatus which is capable of operating, by means of a vacuum pump means, at the temperature of the warm water source, not requiring any addition of conventional energy.
Another object of the present invention is to provide, within the second heat pump system, a prime mover of the positive displacement type with the lowest possible volumetric efficiency in order to derive the maximum power from the existing and available pressure differentials while requiring the least possible mass flow of refrigerant vapors and subsequently requiring the least energy from the water, or fluid, sources.
Other objects and a fuller understanding of this invention may be had by referring to the summary of the invention, the description and the claims, taken in conjunction with the accompanying drawings.